The removal of arsenic (As), a heavy metal ion present in water supplies world-wide, is important for several reasons. Studies have indicated that the deleterious effects of exposure to even small doses of arsenic can be cumulative and may lead to cancer, such as skin cancer, lung cancer, bladder cancer, and kidney cancer, as well as immunological and neurological problems. Several countries in the world, for example, Bangladesh, India, Mexico and the United States to name a few, have naturally-occurring high As levels in drinking water. The seriousness of the problem is exemplified by the new worldwide requirement of As level at no more than 10 mg/L for drinking water (down from 50 mg/L prior to 1993) by the World Health Organization (WHO) [1] and the adoption of the same requirement by United States Environmental Protection Agency (USEPA) (40 CFR Part 141) in January of 2006.
Work done by researchers including those in the United States have shown that magnetite (Fe3O4) particles are very effective in reducing As concentration [as As (III) in Arsenite and as As (V) in Arsenate] from contaminated water. A detailed study of the adsorption of As to magnetite nanoparticles has been performed in terms of particle concentration, pH, ionic strength and temperature. The results suggest that As adsorption is not significantly affected by pH, ionic strength, and temperature ranges [2]. It has also been determined that magnetite particles in the nanodimension (<100 nm) dramatically increases the adsorption capacity of As removal [3]. A patent application on the use of an iron composition based water filtration system for the removal of chemical species containing arsenic and other metal cations and anions has been published [4]. A majority iron component combined with layers of sand, brick, chips, and charcoal was used to create a water filter for filtering inorganic arsenic species and other soluble metal ions out of water. A composite material containing a blend of activated carbon with a large specific area and iron oxide nanoparticles prepared in its presence has been used to remove arsenic in water. However, the procedures for the synthesis of magnetite nanoparticles reported so far in these references are rather tedious, time consuming and expensive.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.